1. Field of Invention
The present invention relates to a resonating piece that utilizes a piezoelectric effect. More particularly, the invention relates to a quartz resonating piece that utilizes a new cut quartz plate, a quartz resonator, and a quartz device.
2. Description of Related Art
Computerization of various devices and development of communication systems have enabled the usage of quartz devices including piezoelectric oscillators in the related art. In particular, quartz crystals can be used as piezoelectric materials in quartz devices because they provide high frequencies and have stable frequency characteristics. Since an AT cut quartz plate (hereinafter “AT cut plate”) can be used to provide a quartz resonator having stable frequency characteristics over a wide temperature range, the related art has used it in quartz devices. This AT cut plate has one side that is parallel to an X axis and is obtained by a cutting operation at a cut angle θ set by clockwise rotation of an XZ plane by 35.25 degrees around the X axis (as viewed from the −X direction to the +X direction of the X axis).
Frequency-temperature characteristics of a quartz resonator formed of the AT cut plate is shown in FIG. 11. In FIG. 11, the horizontal axis indicates the temperature (in ° C.), and the vertical axis indicates the frequency shift (in ppm) from the standard frequency at 25° C.
The related art includes the apparatus disclosed in Japanese Patent No. 3,218,537 and P. C. Y. Lee & Y. K. Yong, “Frequency-Temperature Behavior of Thickness Vibrations of Doubly Rotated Quartz Plates Affected by Plate Dimensions and Orientations”, Vol. 60, No. 7, United States, Journal of Applied Physics, Oct. 1, 1986, p. 2340.